A common combination lock, shown in FIG. 13, comprises: a toothed disk 23 having a gap 232, an inserting hole 231 and a plurality of protruding teeth 233 on the side wall thereof. A sliding ring 24 is provided which has an inserting hole 241 and a gap 242, and is disposed among the protruding teeth 233 of the toothed disk 23. The sliding ring 24 further has a pair of concave recesses 243 disposed on opposing sides of the outer surface of the circumferential wall thereof and a pair of convex protrusions 244 disposed on the internal surface of the circumferential wall, both pairs 243, 244 being disposed in radial alignment. Numeral dials 25 are provided having an inserting hole 252, a plurality of protruding teeth 253 equally spaced with a plurality of withholding holes 254 disposed therebetween, and a plurality of numerals equally spaced on the outer circumference thereof. Elastic fixing rings 26 are provided having an inserting hole 261 in the center, a protruding grain 262 on one side and a pair of convex protrusions 263 facing each other on the internal edge of the hole 261. A ringed controlling slider 27 is provided which has an inserting hole 271, a gap 272, a pair of convex protrusions 273 facing each other on the internal surface of the circumferential wall, a pair of concave recesses 275 are disposed on the outer surface of the circumferential wall, in radial alignment with the convex protrusions 273. The slider 27 also includes a touch-push block 274 possessing a concave recess 276 extending from one side edge thereof. Additionally, a ringed thimble 28 is included which has a protruding block 281, a concave cavity 282, an inserting hole 283 in the center and a pair of convex protrusions 284 disposed on the edge of the inserting hole 283.
In assembling the lock, first the sliding ring 24 is mounted into the cavity formed by the protruding teeth 233 of the toothed disk 23. The convex protrusions 244 are engaged with a pair of concave recesses 211 of a socket 21. Then the convex protrusions 263 of the elastic fixing ring 26 are engaged with the concave recesses 243 of the sliding ring 24 to secure each other.
The numeral dial 25 is connected to the protruding teeth 233 of the toothed disk 23. Further, the thimble 28 secures the above elements by means of a C-shaped ring 212.
In changing the codes, the plurality of sliding rings 24 and the plurality of toothed disks 23 are pushed by pressing the ringed controlling slider 27, which is connected to an elastic element 22 so as to compress the elastic element 22 and make the protruding teeth 233 of the toothed disk 23 separate from the withholding holes 254 of the numeral dials 25. Thus new codes can be set by turning the plurality of numeral dials.
Nevertheless, this common numeral lock has undesirable disadvantages as follows:
1. There are too many types of complicated elements so as to render the locks structure complicated and of high cost. PA1 2. When users want to change the codes, they must keep pressing the ringed controlling slider 27, from the beginning to the end of the operation, with one hand while they are turning the numeral dials 25 with the other hand. Thus, this renders the code setting relatively inconvenient.